being able to hold the bad.

you should be able to say things in therapy like:

'i thought that you had abandoned me'

and the therapist should be capable of processing the origin of the feeling rather than responding defensively

'i did NOT abandon you'.

you should be able to say how you feel without the therapist defending and justifying themself. in order to do this they have to understand (well and truely) that therapy is about understanding the origins of the feelings. of course this can be overdone when people say they feel annoyed because the therapist is regularly 20 minutes late, for example (though there processing the origins can still be useful even though in this instance it would seem that behavioural change would be required).

it is hard... i don't know. partly it is about trust, i guess. i simply don't trust that i can tell my therapist some things because i simply don't know whether he is capable of holding some of my internal states without getting defensive or without having uncontrolable behavioural responses of his own (such as aversion or disgust). time will tell, i guess. but any therapist who thinks trust is all or none is clearly mistaken and people do have limitations in fact.

i do not at all mean to suggest that your therapist isn't a terrific therapist. i do think that the way he handled this was unfortunate, however. i don't suppose... you would have the courage to raise it again? don't matter really whether you do or you don't as things like this have a habit of recurring all on their own...